In France, pétard means joint; of the cannabis variety. The word's origins lie in the fact that "pétard" means "firecracker" or some kind of rocket, so there are two similarities: the shape, and the fact that all of these "pétards" have to be lit. Oh, and they're all fun too. If you're feeling especially lazy, you can simply say "pet". There seems to be no verlan (backslang) equivalent of this word.

A case containing powder to be exploded, esp. a conical or cylindrical case of metal filled with powder and attached to a plank, to be exploded against and break down gates, barricades, drawbridges, etc. It has been superseded.